Conventionally, in a weft knitting machine in which front and rear needle beds are opposed to each other at a needle bed gap, there has been used a complex cam system having a transfer cam which is capable of carrying out an operation for knitting a knitted fabric, and a transfer operation in which delivering and receiving of a knitted loop are carried out between the front and rear needle beds. In a conventional complex cam system, a cam for a transfer operation is formed in an internal area of a needle raising cam for knitting a knitted fabric.
The applicant of the invention has disclosed a complex cam system in which a cam for delivering in the transfer operation is provided outside the needle raising cam (refer to Japanese Examined Patent Publication JP-B2 2-10262 (1990), for example). A latch needle is used as a knitting needle in JP-B2 2-10262. However, a blade for transfer is attached to a side of the knitting needle, and the knitting needle on a delivering side advances to a needle bed gap in such a state that a knitted loop to be transferred is held at a position at which the blade is provided. The knitting needle on a receiving side allows a hook to interpose between the blade and the knitting needle on a delivering side to receive the knitted loop. A transfer cam is provided on the needle bed gap side of the needle raising cam and the knitting needle is provided with two butts at an interval, to switch to a guide for a transfer operation during a guide by the needle raising cam for knitting a knitted fabric. A two knobby-shaped path which is most projected toward the needle bed gap at positions symmetric with respect to a center line passing through a tip of the needle raising cam are formed on the transfer cam as a path for guiding a butt of the knitting needle.
There has been also disclosed a cam holder of a weft knitting machine for guiding a needle body along a two knobby-shaped path by use of a latch needle to allow a delivering operation to carry out (refer to Japan Unexamined Patent Publication JP-A 62-104946 (1987), for example). In JP-A 62-104946, the needle body of a knitting needle is arranged to guide along a path having two knobby-shaped peaks across a center line, on a delivering side of a transfer operation. The knobby-shaped peak through which a butt passes first in association with movement of a carriage needs to precede a path to which the butt is guided by a needle raising cam for knitting, and the path of the butt is arranged to pass through outside a knitting cam, instead of between an inside of the knitting cam and the needle raising cam.
The applicant of the invention has also disclosed a needle manipulating cam for a weft knitting machine which includes a needle body and a slider, and attaches a blade for transfer to the needle body of a compound needle for opening and closing a hook of the needle body using the slider to allow a transfer operation (refer to Japan Examined Patent Publication JP-B2 6-84583 (1994), for example). In JP-B2 6-84583, a delivering operation of the needle body is carried out by a knitted loop delivering cam which is provided so as to project from a tip of a needle raising cam. The knitted loop delivering cam has its peak portion on a center line passing though a peak portion of the needle raising cam, and a butt of the needle body is guided so as to pass though one knobby-shaped path. In JP-B2 6-84583, in order to use the compound needle as a knitting needle to separately drive the needle body and the slider, a cam for driving a slider is provided at a position at which the transfer cam is provided in JP-B2 2-10262.
Conventionally, in a complex cam system for a compound needle, a downsizing of a carriage takes priority. Therefore, as shown in JP-B2 6-84583, a path which guides the butt of the needle body is arranged to be substantially similar to a path which guides to a knit position in a knitting operation. In the delivering of the transfer operation, it is necessary to advance the needle body closer to a needle bed gap than a knitting route in an operation for knitting a knitted fabric. Therefore, a cam having a triangular shape is added to a tip of the needle raising cam for knitting, so that a height of the needle body when advancing to the needle bed gap is further increased. When a delivering of a knitted loop is carried out using a knitting needle which is guided by such a knobby-shaped path, no slack is formed in the knitted loop, for example, at an end of a knitted fabric, when knitting a closed stitch in which a knitted loop is reduced or when knitting normally. Therefore, it becomes difficult that the hook of the knitting needle on a receiving side is introduced to the knitted loop which is held by the knitting needle in a knitted loop delivering side, and is further interposed to between the blade of the transfer and the knitting needle.
As disclosed in JP-A 62-104946, In a case in which the two knobby-shaped path is used for a delivery by the latch needle, the delivery is carried out, when a knitted loop is once pulled down at the first knob and then the needle body is once again projected toward a needle bed gap at the second knob and pulled down once again. Accordingly, a slack can be formed in the knitted loop, and thereby the hook of the knitting needle on a receiving side can be easily inserted to carry out the smooth transfer. However, in JP-A 62-104946, it is necessary to provide a guide path of the needle body for the delivering outside the knitting cam, thereby increasing a size of a cam which is mounted on the carriage as a whole.